LED light sources are also used in great numbers and in many designs for lamps of motor vehicles. LED's most frequently consist of a monocrystal the anode and cathode leads of which are directed from a printed circuit board that controls the intensity of the supplied electric current to prevent overheating of the LED's and shortening of their service life.
One of the important tasks is to ensure sufficient cooling of LED's. It is a well-known fact that the cathode lead of a LED heats up several times more than the anode lead. Therefore, one of the ways of ensuring sufficient cooling is temperature equalization between the cathode and anode part of the LED. As the temperature equalization body must be electrically insulated from the anode and cathode part of the LED, sharing of heat between the cathode and anode part of the LED and the temperature equalization body is limited.
A major obstacle to sufficient cooling of LED's are the entire boards of conductive printed circuits that prevent direct cooling of LED's. As the lighting output of LED's is increasing, the need to remove great amounts of heat that modern LED's emit is rising accordingly. Therefore, LED's have a limited service life due to insufficient cooling.
Devices, especially lamps of motor vehicles, where LED's are used as the light sources are exposed to high ambient temperature differences during operation. These ambient temperature differences must also be overcome by intensive cooling of the LED's. A number of technical designs of prior art are known that strive to improve cooling of light sources consisting of LED's.
The document DE102004036931 (Daimler AG, DE) shows the headlight of a motor vehicle with a light source that contains LED chips (monocrystals) arranged in a row. The principle of the design in accordance with this document is that the anode contact element and the cathode contact element, which are used to lead current to and from each of the chips (monocrystals), are made up of special cooling bodies in the form of mutually insulated plates that lead current and at the same time remove heat from the chip. The plate cooling bodies for cooling of the LED chips (monocrystals) are arranged in parallel next to each other and are electrically insulated from each other. The LED chips (monocrystals) are arranged along the lateral sides of the plate cooling bodies in such a way that the anode contact element of all the chips of the light source is a plate cooler that all the individual chips are connected to by means of electrically conductive wires, and the cathode contact element of all the chips of the light source is another plate cooler whose lateral side the chips of the light source are directly connected to. The plate cooling elements are used to supply and lead away electricity without an inserted conductive printed circuit board. The electrically insulated plate coolers with their main large surfaces arranged adjacent to each other conveniently transfer heat from the cathode plate cooler, which gets heated more, to the anode plate cooler. However, the sum of heat removed from both the plate coolers is low, which results in overheating of the LED chips and their short service life.
The document US20040052077 (Shih Kelvin, US) presents a light emitting diode (LED) having its anode outlet in the form of an anode web and the cathode outlet in the form of a cathode web. The webs are electrically separated from each other and pass into free arms for heat removal. Each free arm passes through a horizontal printed circuit board to control the LED and at its foot it is connected to the conductive circuits of the horizontal printed circuit board by means of a contact connection. A heat equalizer is applied to the cathode as well as anode board by means of electrically non-conductive adhesive to transfer the surplus heat from the cathode side to the anode side and it also ensures air cooling with its free arms. However, a disadvantage of the LED is its low capability to remove heat from the source as the free arms of the webs are part of the printed circuit board and their size, weight and material selection are limited. Thus, the removal of heat from the LED is insufficient.
The document EP1139439 (Relume Corporation, US) shows a light emitting diode (LED) that is made up of one side of a printed circuit board for controlled supply of electricity to the LED and its removal. The anode outlet of the monocrystal of the LED is connected to the anode contact element of the conductive printed circuit board with an electrically conductive wire. The cathode outlet of the monocrystal of the LED consists of an electrically conductive foot of the LED, connected to the cathode contact element of the conductive printed circuit board. The electrically conductive foot fitted with electrically insulating coating passes through the conductive printed circuit board and reaches into a plate cooling element for equalization and removal of heat from the LED. At the side averted from the printed circuit board the plate cooling element is equipped with cooling fins. Heat is removed insufficiently from the electrically conductive foot of the LED source because between the electrically conductive foot and the plate cooling element there must be an electrically insulating layer. The plate cooling element mainly removes heat from the conductive printed circuit board, and therefore it cannot be used for LED's whose consumption of electricity is not controlled by a printed circuit board.
Common disadvantages of the prior art consist in insufficient removal of heat from LED's and a complex structural arrangement of cooling of LED's, which is negatively manifested in the lighting performance and service life of LED's.
The task of the invention is to provide a simple and versatile cooler of a LED light source that will feature a great ability to remove heat even from a higher number of LED's arranged in groups and that will enable higher lighting outputs and a longer service life of LED's.